[TORQUE-1014] Inconsistency in Rails session store and cache store names

The cache store can be accessed now with `:torquebox_cache symbol`:

```ruby
module App
  class Application < Rails::Application
    config.cache_store = :torquebox_store
  end
end
```

I made this default in the docs and template. The `:torque_box_cache` symbol is also available.

Fixes https://issues.jboss.org/browse/TORQUE-1014